Rapid assessment of case recruitment tools to inform integrated surveillance of influenza and other respiratory viruses in Eastern Mediterranean countries

Abstract Influenza‐like illness (ILI) and severe acute respiratory infection (SARI) case recruitment tools from 10 countries were reviewed. The contents of the existing tools were compared against World Health Organization's current guidelines, and we also assessed the content validity (accuracy, completeness and consistency). Five of the ILI tools and two of the SARI tools were rated as having high accuracy against WHO case definitions. ILI completeness ranged from 25% to 86% and SARI from 52% to 96%. Average internal consistency scores were 86% for ILI and 94% for SARI. Limitations in the content validity of influenza case recruitment tools may compromise recruitment of eligible cases and result in varying detection rates across countries.


| BACKGROUND
Influenza is an acute respiratory infection caused by influenza viruses that circulate in all parts of the world. Illnesses range from mild to severe and even death. Hospitalisation and death occur mainly among high risk groups. Worldwide, these annual epidemics are estimated to result in about 3 to 6.5 million seasonal INFLUENZA-associated deaths (4.0-8.8 per 100,000 individuals). 1 For over 70 years, influenza sentinel surveillance systems have been used globally to detect influenza epidemics and assess seasonal patterns and severity in a timely manner for implementing effective management strategies and interventions. 2 The WHO's Global Influenza Programme provides guidance for influenza surveillance. 3 The WHO Regional Office for the Eastern Mediterranean provides operational and technical support for countries in the Eastern Mediterranean Region (EMR) to assist with evidence-informed surveillance practices including the provision of robust tools for accurate and timely detection of influenza and other respiratory pathogens of epidemic and/or pandemic potential. 4 For the purpose of valid data collection and reporting, case recruitment tools used at influenza sentinel surveillance sites need to be robust and methodologically sound to ensure valid case selection.

| AIM
The aim of this rapid assessment exercise was to review existing and available case recruiting tools for influenza-like illnesses (ILI) and severe acute respiratory infections (SARI) from selected countries and assess their content validity.

| METHODS
ILI and SARI case recruitment tools from 10 countries in EMR were reviewed (Afghanistan, Bahrain, Jordan, Lebanon, Libya, Morocco, Saudi Arabia, Somalia, Sudan and Yemen). The content of each country's tool was compared against WHO guidelines 2 and Eastern Mediterranean regional influenza data reporting platform, EMFLU-2.0. 5 Content validity, measuredas (i) accuracy of case definitions, (ii) completeness of needed variables and (iii) consistency and usability of recruitment tools, were assessed.
1. Accuracy was assessed against the current WHO case definition for ILI (an acute respiratory infection with measured fever greater than or equal to 38 C and cough with onset within the last 10 days) and SARI (an acute respiratory infection with measured fever greater than or equal to 38 C and cough with onset within the last 10 days and requires hospitalisation). 1 Two elements were considered in assessing accuracy: (i) statement of case definition criteria listed and (ii) questions eliciting attributes of case definition criteria embedded within the tool which allow for either identification or exclusion of the patient as a case. The combination of these two elements determined the overall accuracy using the matrix below (Table 1).

| RESULTS
The ILI case recruitment tools for 10 countries and the SARI case recruitment tools for nine countries were reviewed. Results are summarised in Table 2.

| Accuracy (case definition)
As seen in Table 2, five of the 10 ILI tools were rated as having high levels of accuracy (Jordan, Lebanon, Libya, Saudi Arabia and Somalia).
These tools contained sufficient information in a clear way to support the purpose and meaning of case definition. Yemen's tool incorrectly noted the fever component of the case definition (greater than 38 C), which resulted in them being classified as 'Low'.
Only two of the SARI tools were classified as having high levels of accuracy (Bahrain and Libya). Six tools (Jordan, Lebanon, Morocco, Saudi Arabia, Somalia and Sudan) received a 'Medium' rating due to not listing the case definition and having incomplete case definition question embedded within their tool. Afghanistan received a 'Low' rating as they did not note whether the case had a cough, an essential element of case definition for both SARI and ILI.

| Completeness
The total number of variables contained in ILI tools ranged from 23 variables (Afghanistan) to 49 variables (Morocco) with a median of 35.5 variables. However, the total number of variables in agreement T A B L E 1 Required criteria elements measuring 'accuracy' of SARI/ILI case definitions embedded in the tool. with the EMFLU-2 database (a possible 41 variables) was as low as 8 (20%) in Bahrain to as high as 39 (95%) in both Libya and Somalia.
Having a tool with more variables did not equate to having higher levels of agreement with EMFLU-2 ( Figure 1).  (Table 2). Longer and shorter tools had lower agreement compared with those closer to the median number of variables (Figure 1).

| DISCUSSION
This rapid assessment has identified some areas of improvement in the identification of cases and the collection of data in some of the existing case recruitment forms.
Case identification was not apparent, nor readily available in many of the case recruitment tools.

| Limitations
There are several limitations in the conduct of this rapid assessment.
Firstly, EMFLU-2 was used as the reference standard, rather than a gold standard. Although it was developed in accordance with WHO requirements, it may not contain all required variables and may con- Attempts were made to obtain ILI and SARI case recruitment tools from all EMR countries. Unfortunately, only 10 countries were able to provide their tools within the timeframe of the evaluation. It is possible that the 10 countries that supplied their tools are representative of all countries in the region; however, this is not possible to assess. As such, other countries in the region may have case reporting tools that rate higher or lower than the case reporting tools evaluated in this study.